Compressor casing



Feb. 6, 1968 R. c. BURNS 3,367,567

COMPRESSOR CASING Filed Aug. 1, 1966 3 Sheets-Sheet l FIG. I .0 22

INVENTOR.

RODNEY C. BURNS.

ATTORNEY.

Feb. 6, 1968 R. c. BURNS COMPRESSOR CASING 5 Sheets-Sheet Filed Aug. 1, 1966 v @E m ill-1Q 8 in I, w n 3 -o Mm \o/ E ATTORNEY.

Feb. 6, 1968 R. c. BURNS COMPRESSOR CASING 5 Sheets-Sheet 5 I Filed Aug. 1, 1966 INVENTOR. RODNEY C. BURNS.

ATTORNEY.

United States Patent Filed Aug. 1, 1966, Ser. No. 569,179 Claims. (Cl. 230-133) This invention relates broadly to rotating machinery. More particularly, this invention relates to gas compressors. Still more particularly, this invention relates to a novel gas compressor casing formed without the necessity of including cast parts as components thereof.

This invention is directed to a casing for a gas compressor including an inlet section, a shell or central body section, and an outlet section in which the individual structu'al parts comprising the sections are composed of plate material formed and united in a predetermined manner.

In gas compression equipment of the kind contemplated, the outlet section normally includes a voluteshaped gas diffuser passage, the cross section of which gradually increases as it progresses around the circumference to collect the gas as it leaves the final stage of compression and to convert the velocity energy of this gas to pressure in an eflicient manner. When an outlet section is formed by casting the metal, the volute diffuser passage is easy to form, taking the shape dictated by the pattern used in making the casting. When forming the outlet section from plate material in which substantially constant cross section parts are employed, it is necessary that the gas difiuser passage be constructed in at least a part of the section during the time the section is fabricated.

This invention contemplates forming the central or cylindrical body section of the casing from late material formed into a cylinder with the abutting edges secured to one another by tack welding. The inlet and outlet sections are formed from two pieces of plate material, the first having a generally arcuate cross section one edge of which is joined to the central cylindiical portion of the casing and the second piece being formed of plate material to which is imparted a reverse curvature. One edge of the second part is joined to the other edge of the first part by welding. Openings are provided in the second part permitting passage therethrough of the power shaft of the machine. The interior of the outlet section is provided with aWall defining a generally helical path so as to define a gas diffuser passage of gradually increasing cross section as desired.

In developing the wall, a series of spaced webs are arranged projecting inwardly from the second part of the outlet section. The webs vary in length and the outer or free end thereof locates the position in the outlet section at which the wall should be disposed. Thus a single plate or series of plates, if desired, connect to the'unattached end of the webs to form the gas diffuser passage between the plate a-nd the interior surface of the other part. The completely welded enclosure is divided into an upper half-and a lower half and appropriate flanges are applied thereto in order that the two sections may be bolted together and may be easily separated should the need arise.

The webs referred to above areprovided with passages permitting drainage of condensate or liquid which may form or collect-inthe portion of the outlet section through which gas does not flow. The diifuser passage wall is provided with openings permitting equalization of pressure between the space defined by the webs and the space accommodating gas flow from the machine.

It is a chief object of this invention to provide a compressor casing that may be readily fabricated by welding sheet or plate metal parts in which the inlet and outlet sections are of a common design enabling manufacturing economies to be realized.

An additional object of the invention is the provision of a gascompressor as described wherein novel gas fiow diffuser passage means are employed.

These and other objects of the invention will be apparent upon a consideration of the ensuing specification and drawings in which:

FIGURE 1 is a front, elevational view of a gas compressor formed in accordance with the invention;

FIGURE 2 is a partial perspective view of a part of the central section and certain of the parts forming the outlet section;

FIGURE 3 is a cross section through the outlet section taken along lines 3-3 of FIGURE 4 illustrating the gas diffuser passage formed in the outlet section;

FIGURE 4 is a cross section of the outlet section taken along lines 44 of FIGURE 1 illustrating the transition duct for directing compressed gas from the difiuser passage outwardly of the machine;

FIGURE 5 is a perspective view of part of the outlet section showing the manner of forming and connecting the transition duct to the outlet section; and

FIGURE 6 is a perspective view of the outlet sectio with one of the parts removed to show the details of the gas diffuser passage wall.

A machine utilizing a rotary power shaft and illustrating the invention is shown in FIGURE 1 as a gas compressor 10 including three primary sections, an inlet section :12, a central section or shell 14, and an outlet section 16. Gas to be compressed enters the inlet section 12 and passes through the central section 14 where it undergoes a plurality of stages of compression. As the compressed gas leaves the central section, it flows from the machine through the outlet section 16, traversing a gas diifuser passage of increasing cross section commonly referred to as a scroll or volute. Pedestal means, not shown, support the machine at a vertical location above the bottom of the machine so that, if desired, the compressor may be mounted over a depression in a floor or ground installation. Reinforcing ribs and grapple lugs are also welded to the sections described above.

The central section 14 is formed by bending or rolling a steel plate of the desired thickness to a cylindrical form and uniting the edges by tack welding. The inlet section 12 is composed of two separate parts, 18 and 20. Part 20 is provided with an arcuate configuration by pressing or spinning a flat circular plate and thereafter removing a section to define a central opening. This formed configuration is commonly known as a flanged only head in the pressure vessel art. Part 18 is also formed from a flat circular plate in a similar manner. In forming part '18, there is a reverse bending operation involved so that the part has a cross section similar to that obtained in forming outlet part 24 shown in FIGURE 2. This shape is commonly known in the pressure vessel art as a flanged and reversed dished head. Appropriate inner strengthening struts, not shown, are secured to the inner surface of part 18 and the part-s 1'8 and 20 are joined by welding. The sub-assembly comprising parts 18 and 20 is secured to one end of the shell preparatory to conducting further fabricating steps on the parts.

The outlet section 16 is also composed of two parts 22 and 24 similar in shape to parts 20 and 18. Prior to uniting parts 22 and 24, cylindrical sleeve 30 is secured to the edge of part 24 defining an opening formed in the part to accommodate the shaft, note FIGURE 3. This sleeve is provided as a housing for the shaft bearing and sealing assemblies employed with the machine. Located 3 inwardly of part 24 is annular wall 32 secured by welding to the sleeve 30. Encircling wall 32 near its outer radial edge is cylindrical ring 34 engaging the inner sur face of part 24 to define a space 35. Spaced gussets 37 divide space 35 into a series of chambers.

Attention is directed to FIGURE 6 which illustrates a preferred manner of constructing the diffuser passage defining wall 36. At predetermined spaced locations about the inner surface of part 2.4, Web members 38 are disposed. The webs are connected to the part 24 by welding an edge of the web to the inner surface. Each web 38 has a different height than its adjacent web so that the outer unattached edges 39 substantially define a helix. The outer edges 39 are connected by the wall 36 which now assumes the helical path formed by edges 39. Once the part 22 is secured by welding in the manner shown in FIGURES l and 3 to the part 24, the wall defines with the inner surface of part 22 and a portion of the inner surface of part 24 a gas diffuser passage of varying width.

In the construction of a gas compressor in accordance with this invention, it is necessary to include a connection to the outlet section 16 so that compressed gas flowing from the gas diffuser may pass to a discharge line forming part of a system served by the compressor. As pointed out above when the parts 22 and 24 are connected, there results a distorted torus-shaped structure. The means enabling flow of the compressed gas from the gas diffuser passage in the torus includes a transition duct 50 having a particular configuration.

It has been found practical in constructing the transition duct to replace a segment of the annular ring 34 with a plate 52 forming in effect a chord of the circle defined by the ring. The plate then extends through the torus and connects to the part 24 at weldment 54. The plate 52 has an enlarged portion 56 the outer edge 58 of which abuts against the inner surface of part 22 when the parts are joined.

In order to describe the connection between the transition duct 59 and the outlet section 16, reference may be had to FIGURE wherein dotted lines depict the joint between either the parts forming the duct or the welded connection between the duct and the torus formed by the parts 22 and 24. The dotted lines thus indicate the boundary of the material removed from the section. Dotted line 59 together with a companion line on the other side of the line of juncture between parts 22 and 24 and together with a cross cut line 60 receive the end and adjacent side edges of a section 64 of the transition duct. Dotted lines 62 swing downwardly at a first given radius and dotted lines 63 swing inwardly at a second radius. The lines 62 and 63 define the junction between gusset plates 65 of a non-planar shape. An arcuate section 66 connects to the outlet section, the lower edge of the gusset plates and the section 64 at weld lines 67.

Section 64 is provided with a cross section that changes throughout its height from a relatively shallow U-shape at its upper end (the connection shown at 59, 60) to a substantially semi-circular cross section at its lower end. Thus gusset plates 65 provide a connection between the edges of section 64 and the curved surface of the torus so that gas may flow from the outlet section to a conduit system, not shown.

As pointed out above, a gas compressor casing of the kind described should be divided into an upper half and a lower half in order that access may be had to the internal operating elements of the machine. As the invention has been described, the parts have been united so as to form a complete casing. In practice, however, the parts 18, 20, 22 and 24 have substantial portions provided with slits through the center thereof so that after assembly into a unit a small amount of fiame cutting by a torch is all that is necessary to separate the assembly into upper and lower halves. It has been stated above that the central section is formed by rolling a plate into a cylinder and tack welding the abutting edges. The cylinder is then cut along diametrically opposed regions, one of which is the tack welded seam to form two separate halves.

After the casing including the inlet, outlet and central sections has been formed into two halves, flanges A are welded thereto in the appropriate places. In addition, stiffening ribs B and pedestal supports C are likewise welded to the individual halves preparatory ot assembling, within the casing, the operating parts of the gas compressor. It will thus be appreciated that a casing for a multi-stage gas compressor may be fabricated by employing plate material welded together. One important advantage obtained by employing plate material connected by welding is realized when unusually low or high temperature gas is processed. The individual parts may be of different materials to suit the temperature existing at that location in the casing whereas if a casting is used it ordinarily is necessary to use the same material throughout.

While I have described a preferred embodiment of my invention, it is to be understood that the invention is not limited thereto since it may be otherwise embodied within the scope of the following claims.

I claim:

1. A gas compression machine comprising a casing including a central section, an inlet section and an outlet section arranged to provide a path for the flow of gas through the machine, the outlet section comprising a first substantially annular part having an opening and a second substantially annular part having an opening, said first and second parts being joined in edge-to-edge contact with the opening in registry, a plurality of webs extending from the inner surface of said second part, at least two of said webs being of unequal length, the free ends of said webs de fining a substantially helical path of increasing width, wall means attached to the edges of said webs opposite the connection thereof with said second part and discharge means connected to said outlet section for discharging gas flowing from said path.

2. A gas compression machine as defined in claim 1 wherein said outlet section includes a sleeve member positioned in said opening, a second wall encircling said sleeve, said wall providing support for a second edge of said webs.

3. A gas compression machine as defined in claim 2 wherein a portion of said second wall is provided with an arcuate configuration and a portion is provided with a linear disposition.

4. A gas compression machine as defined in claim 3 wherein said discharge means includes a transition duct forming an extension of the section of the path utilizing the linear portion of the second wall.

5. A gas compression machine as defined in claim 4 wherein said webs are provided with openings for flow of liquid, and said 'wall is provided with openings for equalization of pressure.

References Cited UNITED STATES PATENTS 1,699,581 5/1928 Spencer 230133 2,285,338 6/1942 Kidney 230133 3,188,966 '6/1965 Tetlow 230-133 FOREIGN PATENTS 23,923 of 1906 Great Britain.

HENRY F, RADUAZO, Primary Examiner. 

1. A GAS COMPRESSION MACHINE COMPRISING A CASING INCLUDING A CENTRAL SECTION, AN INLET SECTION AND AN OUTLET SECTION ARRANGED TO PROVIDE A PATH FOR THE FLOW OF GAS THROUGH THE MACHINE, THE OUTLET SECTION COMPRISING A FIRST SUBSTANTIALLY ANNULAR PART HAVING AN OPENING AND A SECOND SUBSTANTIALLY ANNULAR PART HAVING AN OPENING, SAID FIRST AND SECOND PARTS BEING JOINED IN EDGE-TO-EDGE CONTACT WITH THE OPENING IN REGISTRY, A PLURALITY OF WEBS EXTENDING FROM THE INNER SURFACE OF SAID SECOND PART, AT LEAST TWO OF SAID WEBS BEING OF UNEQUAL LENGTH, THE FREE ENDS OF SAID WEBS DEFINING A SUBSTANTIALLY HELICAL PATH OF INCREASING WIDTH. WALL MEANS ATTACHED TO THE EDGES OF SAID WEBS OPPOSITE THE CONNECTION THEREOF WITH SAID SECOND PART AND DISCHARGE MEANS CONNECTED TO SAID OUTLET SECTION FOR DISCHARGING GAS FLOW FROM SAID PATH. 